Incorrect Date Conversion in nodered, moment.js works fine.

[brmo]

From Home Assistant, I get the following data:

entity_id: "binary_sensor.garage_camera_motion"
last_changed: "2018-06-01T18:13:03.909192+00:00"

Then using this project, i am taking that last_changed value and converting to "dddd, MMMM Do YYYY, h:mm:ss a" the result I get is Tuesday, June 19th 2018, 11:13:03 am. Which is off by 18 days. The time is correct as I have it converting from UTC to US/Pacific time.

If I take that exact time string and use https://codepen.io/widmoser/pen/NNOQEx?editors=1111 to test moment.js using the following, its correct.

const time = moment('2018-06-01T18:13:03.909192+00:00').format("dddd, MMMM Do YYYY, h:mm:ss a");
alert(time);

Am I doing something wrong using the plugin?

[shrickus]

Well, it's definitely not a problem in the output (formatting) -- even if I use the default ISO-8601 formatting, the UTC "timestamp" returned is 2018-06-19T18:13:03.909Z

However, if I use plain JavaScript to parse that date string, it is correctly interpreted:

> new Date("2018-06-01T18:13:03.909192+00:00")
2018-06-01T18:13:03.909Z

So what is happening inside the moment node? Well, here's the relevant section of code:

  default: 
        node.log(node.inTz.split('/')[0]); 
        var prefOrder = {preferredOrder: {'/': 'DMY', '.': 'DMY', '-': 'YMD'} }; 
        if ( (node.locale.toLowerCase().replace('-','_') === 'en_US') || (node.inTz.split('/')[0] === 'America') ) { 
          prefOrder = {preferredOrder: {'/': 'MDY', '.': 'DMY', '-': 'YMD'} }; 
        } 
        inpFmt = parseFormat(inp, prefOrder); 

So the next question is... what input format is being determined by the moment-parseformat library?

> var parseFormat = require('moment-parseformat');
> parseFormat("2018-06-01T18:13:03.909192+00:00"):
'YYYY-MM-DDTHH:mm:ss.SSSD2Z'

Interesting -- but also clearly wrong! So the six digits representing microseconds were interpreted as 3-digits (SSS), followed by the day of the month (D), followed by a literal number (2), followed by the UTC timezone (Z). Removing the extra 3 decimals of precision does fix the problem:

> parseFormat('2018-06-01T18:13:03.909+00:00')
'YYYY-MM-DDTHH:mm:ss.SSSZ'

So this is clearly a bug in the underlying dependent library, which according to package.json is version 2.2.1 -- let's see if the new version 3.0.0 from 11 days ago has the same issue:

C:\NODE\node_red>npm install moment-parseformat@3
+ moment-parseformat@3.0.0
added 1 package and updated 1 package in 1.907s

C:\NODE\node_red>node
> var parseFormat = require('moment-parseformat')
> parseFormat('2018-06-01T18:13:03.909192+00:00')
'YYYY-MM-DDTHH:mm:ss.SSSD2Z'

Yep, no better -- time to open an issue against that library. As you are the one who found the bug, I'll leave that up to you. Good catch!
--Steve

[brmo]

Steve,

Thanks for that excellent diagnosis. I will get this issue created on the library.

--Brian

[TotallyInformation]

Guys, many thanks for sorting this without my input!! :) 💯

[chimpy]

This issue is going to come up again as the Home Assistant/Node Red combo becomes more and more popular I think.

I have a relative time moment node converting my timestamps to "fromNow". Mostly they work, occasionally they are in the future, and sometimes they are way too far in the past. Some examples:

"2019-02-27T11:02:04.709227+00:00" --> "2019-02-27T11:02:52.887109+00:00"
These dates were considered "5 days" apart.

"2019-02-27T11:04:23.209098+00:00" --> "2019-02-27T11:05:40.271300+00:00"
This was "in a month".

"2019-02-27T11:03:06.609682+00:00" --> "2019-02-27T11:03:09.012704+00:00"
This was correctly interpreted as "a few seconds ago".

I will strip the precision from the timestamp and hopefully the issue will be resolved.